Patent Literature 1: JP 2014-78801 A (corresponding to US 2015/0254909 A1)
Patent literature 1, for example, discloses a technique that prevents a depletion of identification information. Patent literature 1 relates to a repeating device. The repeating device relays transmission and reception of a diagnosis frame between an electronic control apparatus connected to two or more LANs and a first tool performing a fault diagnosis of these electronic control apparatus. Any one of the LANs is connected with a second tool performing wireless communication with a center. The repeating device relays transmission and reception of the diagnosis frame between the second tool performing the fault diagnosis according to an instruction from the center and each of the electronic control apparatus. The repeating device converts identification information of the diagnosis frame into identification information used in the fault diagnosis by the first tool when relaying between the second tool and the electronic control apparatus.